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Fe Cr multilayers with monatomic Sn layers embedded in the Cr layers were grown epitaxially on MgO(001) substrates, and the magnetic hyperfine field at the 119Sn nuclear sites was examined using Mossbauer spectroscopy. It was found that nonzero hyperfine field is induced at the Sn sites at room temperature and that the value reduces drastically from 10 to 2 T when the Cr layer thickness decreases from 80 to 10 A. The result indicates that the Cr layers are agnetically ordered even when the thickness is very small and that the magnetic moments of Cr become smaller as the Cr layer thickness decreases.

The magnetic properties of TM/Eu (TM5V, Cr, Fe, Co, Ni, Cu, and Nb) multilayers have been studied by 57Fe and 151Eu Mo¨ssbauer measurements at 4.2 and 300 K. The 57Fe Mo¨ssbauer spectra at 4.2 and 300 K of the Fe/Eu multilayers were fitted with two components: one with hyperfine parameters typical of bulk a-Fe, and the other one with a reduced magnetic hyperfine field, which is attributed to the interface region. The 151Eu Mo¨ssbauer spectra of TM/Eu at 4.2 K were similarly analyzed with two components: component A with hyperfine parameters similar to bulk Eu metal, and component B with a reduced magnetic hyperfine field.Variation of the Eu layer thickness for the systems Fe/Eu and V/Eu showed an enhancement of component B relative to component A with decreasing Eu layer thickness, supporting the analysis with two components given above. The latter component is attributed to the interface region. Possible explanations for the reduction of the magnetic hyperfine field of component B are discussed.

SUMMARYThe C57B1/6 susceptible (BegS) and its resistant (Begr) congenic mouse, previously developed by retrogressive backcrossing, were infected with 1 × 106 colony-forming units (CFU) of Mycobacterium avium and bacterial growth and their immune responses during the early and prolonged periods of infection were examined. There was a high proliferation in the liver and spleen of BegS mice, whereas no proliferation was observed in the Begr mice. Similarly, the sizes and weights of these organs were much higher than those of their Begr counterparts. The size and number of granulomas in Begr were also found to be higher than those of Begr. The CD3+ and CD4+ subsets increased dramatically in both mice during the early stage of infection. However, in the later phase of the infection, these populations decreased dramatically in Begr mice, but not in Begr mice, resulting in a depression in cell-mediated immune responses. No significant decrease in cellmediated immune responses was observed in Begr mice even after prolonged infection. ELISA was performed to determine the antibody levels in both mice, and it was found that serum IgG and IgM levels in Begs were comparatively higher than those in Begr mice throughout the period of infection. The Beg gene therefore may have an important role in the maintenance of resistance not only in the early phase but also in the later phase of Myco. avium infection.

By means of an electron beam deposition technique under ultrahigh vacuum Co/Au(001) superlattices were prepared on GaAs(001) substrates with a 500 AA thick Au(001) buffer layer. The superlattices were characterized by reflection high-energy electron diffraction (RHEED), and X-ray diffraction. The authors found that well defined single-crystalline Co/Au(001) superlattices can be obtained only for samples with Co layer thickness below about 10 AA. The results from X-ray diffraction measurements indicate a lightly strained BCC structure for Co layers with the lattice constants a/sup ///=2.88+or-0.01 AA in the film plane and aperpendicular to =2.78+or-0.02 AA. along the growth direction.

The Ginzburg-Landau coherence lengths were evaluated for C 60 -based superconductors by fitting measured magnetization data with the renormalization theory of the fluctuation. The derived coherence lengths are 21±1 and 13±1 A for K 3 C 60 and Rb 3 C 60 , respectively, which are preliminary results but are apparently smaller than the reported values obtained from H c2 (0) with mean field theory.

X-ray diffraction analyses of Fe/Au(001) superlattice films have revealed a body-centred tetragonal (BCT) structure with c/a=1.1 for Fe layers thinner than 1.0 nm when Au layer thicknesses are 3.0 nm. The perfect in-plane lattice matching was confirmed by off-axial measurements. The observed in-plane lattice parameter, a=0.2875 nm for BCT Fe, is close to the lattice dimension of bulk BCT Fe. However, profile analysis of axial scans have indicated that the Fe(002) lattice spacing along the growth direction has expanded. Such a tetragonal distortion cannot be explained by the normal elastic theory. The observed BCT structure of Fe would be a transient state on the BCC-FCC deformation path stabilized by a size effect or an interface effect. The tetragonal distortion is almost relaxed when Fe layers are thicker than 2.0 nm.

The temperature dependence of the magnetization of Fe/Au multilayers was investigated using a SQUID magnetometer in the temperature range from 10 to 90 K with an external field of 10 kOe. The samples prepared by vacuum deposition consist of the bilayers (Fe(10 AA)/Au(d))n, where d=20, 50 or 100 AA and the number n of bilayer repetitions is from 1 to 12. The temperature dependence closely obeys the relation 1-M(T)/M(10 K)=CTalpha and, as the number n increases, the exponent alpha increases from 1.10 (n=1) to 1.55 (n=10) for d=50 AA. The crossover behaviour of alpha as a function of n is qualitatively explained by a simple spin-wave model.

Mutants of human immunodeficiency virus type 1 (HIV-1) and type 2 (HIV-2), which have been shown to be infectious in established cell lines, were tested for ability to replicate and induce syncytium formation in human peripheral blood mononuclear cells (PBMC). The vpu mutant of HIV-1 showed depressed kinetics of replication in an established T cell line, as reported previously, but in PBMC, its replication was similar to that of the wild type virus. The vpx gene of HIV-2 was required for efficient virus propagation in PBMC, but not in an established T cell line, as previously reported. However, the growth rates of the vpx mutant in PBMC preparations from two individuals were different. The results of experiments on infection of PBMC with the vif and vpr mutants of HIV-1 and HIV-2 were essentially consistent with previous results of infection of established T cell lines. No negative effect of the nef gene products of HIV-1 and HIV-2 was observed. The abilities of the wild type virus and the mutants of HIV-1 to induce syncytium formation in both PBMC and established cell lines were similar. In contrast, neither the wild type nor any of the mutants of HIV-2 induced syncytium formation in PBMC. These results suggest that the functions of some genes can be detected only in mixed populations or primary cells such as PBMC. Studies on the roles of these genes in PBMC may provide a better understanding of their functions in vivo.

Elastic and thermal properties of Au/Ni superlattices have been investigated by x‐ray diffraction on a synchrotron radiation source at the Photon Factory. An elastic response of [Au(10 A)/Ni(10 A)]50 to hydrostatic pressure generated by a diamond anvil cell has been measured in the layer‐stacking direction. Its compressibility obtained from the pressure dependence of its superlattice period (Λ vs P) shows an anomalously small value compared with either bulk Au or Ni metal. Linear thermal expansions has also been measured by a similar method (Λ vs T). A significant anisotropic behavior between the layer‐stacking and in‐plane direction was found in both [Au(10 A)/Ni(10 A)]50 and [Au(4 A)/Ni(4 A)]210.

Structures of Mn/Sb multilayered films have been investigated by X-ray diffraction. MnSb/Sb superlattice films are obtained when the nominal thicknesses are (Mn(1 AA)/Sb(50 AA))90 and (Mn(2 AA)/Sb(50 AA))90. Ultrathin layers of MnSb are formed by interfacial reaction in these samples with keeping an epitaxial orientation of (00.1)MnSb//(00.1)Sb; (11.0)MnSb//(11.0)Sb. These films have fibre texture structures with an in-plane coherence length of about 300 AA. The distribution of growth orientation is approximated by a Gaussian distribution function with a half-width of about 10 degrees . The analyses of diffraction intensities indicate that (i) the texture structure causes a monotonic reduction of peak intensity with increase of scattering vector including fundamental reflection and (ii) that layer thickness fluctuations in the range of one or two monolayers cause peak broadening and intensity reduction only for the higher-order satellite reflections. Observed satellite intensities could be reproduced by a model calculation which takes into consideration these two effects.

An NiFe (200A)/Cu (200A)/NiFe (50A) trilayer film of submicron width was prepared, and the noncoupled-type giant magnetoresistance (GMR) effect was investigated. Magnetization reversal in a single submicron-sized magnetic wire was sensitively detected through a sudden jump in resistance due to antiparallel alignment of two NiFe layers. It was demonstrated that an artificially introduced neck in the wire acts as an obstacle to magnetic domain wall propagation.

Mossbauer spectroscopy with 151Eu nuclei was applied to study magnetic properties of Fe/Eu multilayers as a function of the Eu layer thickness. The Mossbauer spectra at 4.2 K for [Fe(40 A)/Eu(x A)] with x=70, 100, and 200 consist of two magnetic components: a major component with hyperfine parameters close to those of bulk Eu metal and an additional component with a smaller hyperfine field. The latter component is attributed to Eu at the interface region. The spectrum at 4.2 K for [Fe(40 A)/Eu(30 A)] has only a component with a reduced hyperfine field, indicating that the Eu layers lose the bulk magnetic properties.

Magnetic structures of epitaxial Cr(001)/Sn multilayers, where monatomic Sn layers are periodically embedded in a Cr(001) film, were studied using neutron diffraction and Mössbauer spectroscopy. It was found that spin-density-wave (SDW) antiferromagnetic structures with the modulation along the perpendicular direction to the film plane are stabilized at low temperatures. The wavelength of the SDW discretely changes as a function of the superlattice period. The enhanced magnetic moments of Cr at the Cr/Sn interfaces are thought to pin the antimode of the SDW modulation at the interface, resulting in the SDW with the modulation harmonic to the superlattice period.

The haematological mechanisms in the course of liver abscess formation were evaluated. They were examined by employing viable cells of Fusobacterium necrophorum subsp. necrophorum and Fusobacterium necrophorum subsp. funduliforme in comparison with their endotoxins. Whole cell infection with F.n. necrophorum led to neutrophilia and to a concomitant monocytosis in parallel with those responses induced by the in vivo injection of its endotoxin. Viable infection with F.n. funduliforme was characterized by a sustained endotoxin-related monocytosis against neutropenia. The stimulatory impact of endotoxin on monocytes when released from a viable F.n. funduliforme infection suggested an inherently peculiar mechanism which differed from the induction of both neutrophilia and monocytosis when F.n. funduliforme endotoxin was administered alone. The neutrophilic inducing capacity of the F.n. necrophorum endotoxin was equally illustrated by its positive chemotactic effect on polymorphonuclear neutrophils in vitro. The data presented here emphasize the virulence of F.n. necrophorum viewed in reference to changes in leucocyte trafficking and as complemented by a relatively high endotoxin content.

The endotoxins from two recently-classified subspecies of Fusobacterium, namely F. necrophorum subsp. necrophorum and F. necrophorum subsp. funduliforme, were compared. Chemical analysis of the isolated endotoxins revealed that they were clearly different. Distinct levels of polysaccharides were demonstrated. The endotoxins isolated were devoid of heptose and 3-deoxy-D-manno-octulosonate (KDO). The endotoxins of F. n. necrophorum and F. n. funduliforme contained lipid A in a ratio of 4:1 which may account for the variations in their virulence.

Fe/Cr multilayers with monatomic Sn layers embedded in the Cr layers were grown epitaxially on MgO(001) substrates, and the magnetic hyperfine field at the 119Sn nuclear sites was examined using Mössbauer spectroscopy. It was found that nonzero hyperfine field is induced at the Sn sites at room temperature and that the value reduces drastically from 10 to 2 T when the Cr layer thickness decreases from 80 to 10 A. The result indicates that the Cr layers are magnetically ordered even when the thickness is very small and that the magnetic moments of Cr become smaller as the Cr layer thickness decreases.

PbSe/SnSe superlattice, phase transition, high pressure, SR x-ray diffraction) Synchrotron x-ray diffraction experiments have revealed successive phase transitions in epitaxially-grown PbSe/SnSe superlattices. The transition pressures from the low-pressre cubic B1- to the high-pressure orthorhombic B16-type structures are observed to vary systematically depending upon thickness of the PbSe layer. For example, a [PbSe(36A)/SnSe(12A)]19, with the B1 structure in both layers stabilized in its asgrown state, undergoes the [B1/B1]-to-[B1/B16] and [B1/B16]-to-[B16/B16] structural transitions at 1.9 and 3.8GPa, respectively. This result is in contrast to their bulk data that the B1-to-B16 transition takes place at 5.3GPa in PbSe while the B16 phase is stable in SnSe at atmospheric pressure.

Haemolytic activity of two subspecies of Fusobacterium necrophorum was compared in vitro and in vivo. F. necrophorum subsp. necrophorum (Fnn) showed a stronger activity than F. necrophorum subsp. funduliforme (Fnf) in vitro. Haemolytic activity of Fnn and Fnf was 57.97%+/-1.90 and 17.33%+/-1.44, respectively, compared to complete haemolysis by distilled water. In the mice injected with Fnn, haemolysin was detected in the liver at a titre of from 1 : 16 to 1 : 128, and Fnn was recovered from all mice at a viable bacterial count of 10(5) to 10(6) cells per gram liver tissue. In the mice injected with Fnf, haemolysin titre was1 : 2 to 1 : 32. No liver abscess was formed. The viable count of recovered bacteria was 10(3) to 10(5) cells per gram, except for two mice in which no Fnf was detected. The results suggest that haemolysin might be a virulence factor in this species.

The presence of cellular membrane proteins on human T cell leukemia virus type I (HTLV-I) was examined. ICAM-1 and MHC-IIDR, which were highly expressed on MT-2 cells but not on MOLT-4#8 cells, became detectable on HTLV-I-binding MOLT-4#8 cells. Furthermore, a batch of other cellular molecules including LFA-1, ICAM-1, LFA-3, MHC-I, MHC-IIDR, and CD4 became detectable on HTLV-I-binding BW5147 cells, a mouse T-lymphoma cell line, which were able to adsorb HTLV-I. The detectable levels of these molecules were correlated with those expressed on MT-2 cells. The detectable levels of the cellular proteins of human decreased by pretreatment of HTLV-I with sera from HTLV-I seropositive individuals but not from seronegatives. These results indicate that HTLV-I envelope carries cellular membrane proteins derived from the host cell.

The p19 matrix (MA) protein of human T-cell leukemia virus type I (HTLV-I) was exposed on the surface of MOLT-4#8 cells in the very early step of the virus infection. Transfer of the virus-binding MOLT-4#8 cells from 4 degrees C to 37 degrees C resulted in increased detection of the viral gp46 and p19 MA protein on the cells, which was, however, inhibited by 4 degrees C or cytochalasin B treatment. These data showed that increased temperature and fluidity of the cell membrane were required for the increased detection of gp46 and p19 after viral adsorption. On the other hand, exposure of the p19 MA protein was not observed on the virus-treated U937 cells although gp46 was detected. This was not due to inefficient binding of the HTLV-I to the U937 cells, since the methanol-fixed cells were p19 MA protein-positive. MOLT-4#8 cells induced marked cell fusion when co-cultured with MT-2 cells, but U937 cells induced no fusion. All of these results indicated that these two cell lines differed in the property of plasma membrane in terms of degradation of HTLV-I envelope after viral adsorption. Uncoating of the HTLV-I might occur on the plasma membrane, especially on MOLT-4#8 cells.

In May 1994, about fifty Japanese quails out of ninety being bred for experimental purposes at Miyazaki University died of acute septicemia within a few days. At autopsy, there were no gross pathological lesions, however, severe bacteremia was observed in all cases. Bacterial examination revealed the presence of Pasteurella multocida in blood and several organs in pure culture and they were of Carter's capsular type A, Heddleston's type 3-4 and Namioka's type O-8-9. The LD50 of bacteria in quails and mice were 4.3 x 10(4) cfu and 3.9 x 10(2) cfu, respectively. All of the three chickens experimentally infected with 4 x 10(4) of the isolate died within 20 hr after the infection and several bacteria were recovered from their blood and organs. This, to our knowledge, is the first report on an outbreak of fowl cholera in Japanese quails in Japan.

Magnetoresistance (MR) properties were studied in Cu/Co/Cu/Ni80Fe20 system, and a large MR ratio was observed in weak external fields. In the course of field sweeping, these two magnetic components (Co and Ni(Fe)) are oriented antiparallel, because of the difference of coercive forces, and then the resistivity is greatly enhanced. The MR ratio was observed to be 10% at 300K, and 32% at 20K, respectively, in a multilayer \Cu(55Å)/ Co(25Å)/Cu(55Å)/Ni80Fe20(25Å)] ×15.

It was found that high current density needed for the current-driven domain wall motion results in the Joule heating of the sample. The sample temperature, when the current-driven domain wall motion occurred, was estimated by measuring the sample resistance during the application of a pulsed current. The sample temperature was 750 K for the threshold current density of 6.7×1011 A/m2 in a 10-nm-thick Ni81Fe19 wire with a width of 240 nm on thermally oxidized silicon substrate. The temperature was raised to 830 K for the current density of 7.5×1011 A/m2, which is very close to the Curie temperature of bulk Ni81Fe19. When the current density exceeded 7.5×1011 A/m2, an appearance of a multidomain structure in the wire was observed by magnetic force microscopy, suggesting that the sample temperature exceeded the Curie temperature.

Detailed magnetic structure of spin-density waves (SDWs) in epitaxial Crs001d /Sn multilayers was investigated by neutron scattering combined with Mossbauer spectroscopic studies. Monatomic Sn layers were embedded in 240-nm-thick Crs001d films with varying the periodic spacing from 4.2 to 16.2 nm. All samples were revealed to be a commensurate antiferromagnetic (CAF) phase at 300 K. The CAF structures changed to incommensurate SDW states with complex wave forms whose wavelength are controlled by the artificial periodicity at low temperatures although the CAF structure in the sample with the period of 4.2 nm persisted even at 10 K. The phase transition depends on the thickness of the Cr layers intervening between Sn monatomic layers. An appreciable phase slip in the SDW was observed during the phase transition in the sample with the period of 10.2 nm. The SDW structure is discussed by taking account of the competing forces between the nesting of Fermi surface and a pinning of antinodes at the Sn monatomic layers.

Magnetic structures of epitaxial Cr 001 =Sn multilayers, where monatomic Sn layers are periodically embedded in a Cr(001) film, were studied using neutron diffraction and Mo¨ssbauer spectroscopy. It was found that spin-density-wave (SDW) antiferromagnetic structures with the modulation along the perpendicular direction to the film plane are stabilized at low temperatures. The wavelength of the SDWdiscretely changes as a function of the superlattice period. The enhanced magnetic moments of Cr at the Cr=Sn interfaces are thought to pin the antimode of the SDW modulation at the interface, resulting in the SDW with the modulation harmonic to the superlattice period.

The magnetism of Cr thin films in Fe/Cr multilayers was studied using 119Sn subatomic layers inserted in the Cr layers as a Mo¨ssbauer probe for Cr layer thickness from 10 to 160 A. The size and direction of the Cr magnetic moments were inferred from the size and direction of the magnetic hyperfine fields at the Sn nuclear sites. The detected magnetic hyperfine fields indicate that the Cr magnetic moments reduce as the Cr layer thickness decreases, while they do not remarkably change as a function of the distance from the Fe/Cr interface. The magnetic hyperfine fields for the samples grown at 200 °C are smaller and more oriented to the film plane than for the samples grown at room temperature. These observations suggest that the magnetic frustration resulting from Fe/Cr interface imperfections is accommodated by the reduction of the Cr magnetic moments for the samples grown at elevated temperatures, whereas it is accommodated by the reorientation of Cr magnetic moments toward the perpendicular direction to the Fe magnetic moments for the samples grown at lower temperatures.

A new class of corrugated multilayers has been grown on silicon substrates which have (111) faceted grooves etched on their surface. These structures can be probed by conventional means with current at an angle to the plane of layers (CAP) as well as CIP. This angle is fixed by: the depth to width ratio of the grooves (which determines the angle θ), and the angle φ of the current probes with respect to the grooves. We have prepared multilayers of [Co(12 A) Cu(t)NiFe(12 A) Cu(t)]y with t=58 and 116 A, and y=167 and 91 repeats, respectively; and have varied φ from 0 and 90° while θ is held fixed at 54.7°. We find the data is very well fit to the theoretical expression for CAP resistivity in terms of the more conventional CIP and CPP resistivities. From measurements of the CIP and CAP–MR’s on these corrugated multilayers we are able to predict the CPP–MR for these structures.

Mossbauer experiments were made utilizing Co57or Fe57as a microprobe for studying the magnetic properties of ferromagnetic metal surfaces. For the emission spectroscopy, carrier-free Co57atoms were electrodeposited on a surface of bulk iron. The absorption spectroscopy was applied to a sample whose surface was selectively enriched with Fe57. In both cases, the spectra at 4.2 K showed that all iron atoms in the surface are ferromagnetic, but the reduced hyperfine field suggests a partial decrease of the local magnetic moment.

Multilayered films are prepared by the alternate deposition of Mn and Sb in ultrahigh vacuum. On deposition, Mn atoms react with Sb atoms to form a ferromagnetic compound MnSb at the interface. The MnSb layers grow epitaxially on thick Sb layers. By utilizing this epitaxy, ultrathin (less than 10A) MnSb layers are sandwiched between thick (50A) Sb layers. The resulting superlattice films are ferromagnetic even when each MnSb layer thickness is less than 5A.

Superlattice films consisting of ferromagnetic Fe and antiferromagnetic Mn were prepared by ultra-high-vacuum evaporation. The alternate stacking of BCC Fe (110) and alpha -Mn (110) lattice planes when the superlattice periods are in the range from 40 to 80 AA and the Fe and Mn layer thicknesses are equal was confirmed by X-ray diffraction. The films have fibrous textures which are composed of coherent grains of approximate dimensions of 100 AA in the film plane and 200 AA along the growth direction. The distributions in the growth orientation are within 10 degrees . Mossbauer spectra indicate that alloy layers are formed at the interface regions and that the degree of atomic intermixing is rather extensive at the interfaces, where Fe atoms are deposited on Mn layers. The thicknesses of the alloy layers are in the region of 10 AA. When Fe layers thinner than 15 AA are sandwiched by Mn layers, the structure is changed significantly because of alloying. The Mossbauer spectra show unresolved magnetic splitting, with the magnetic hyperfine field widely distributed in the range from 0 to 200 kOe (100 kOe on average). The magnetisation curve strongly depends on the external field and also on the thermal history. The properties of Fe-rich layers are similar to those of the Fe-Mn amorphous alloy and the magnetic behaviour of the multilayers is interpreted as mictomagnetism.

Multilayered films composed of iron metal and amorphous carbon have been investigated by Mossbauer spectroscopy. When iron layers are very thin (8 AA and 15 AA), reduced magnetic hyperfine fields with distributions are observed, which indicate that amorphous Fe layers containing carbon atoms are formed. Mossbauer spectra of a sample with 30 AA Fe layers and of an interface-selectively 57Fe-doped sample indicate that the structure of the major portion of the Fe layer is BCC but amorphous Fe-C alloy layers are formed at BCC-Fe/amorphous-carbon interfaces, the thickness of which is estimated to be about 5 AA.

The wavelength dependence of the X-ray diffraction peak intensity in the small-angle region has been measured on two Fe/Mn superlattice films using synchrotron radiation. Peak intensities are found to be greatly enhanced at a wavelength slightly longer than the K-absorption edge of the Mn atom (1.896 AA), where the contrast in X-ray scattering power of the adjacent Fe and Mn layers becomes significantly large because of the effect of anomalous dispersion. Higher-order reflections up to the seventh are observed for (Fe(15 AA)/Mn(50 AA))40 and up to the third for (Fe(20 AA)/Mn(20 AA))100. Analysis of the peak width and intensity reveals intermixing of the atoms extending over several atom layers ( approximately 10-12 AA) at Fe/Mn interfaces and the fluctuation of the superlattice period within approximately 3-4 AA.

Fusobacterium necrophorum biovar A and biovar B were examined for haemagglutinability and ability to adhere to cells. Six biovar A strains agglutinated tannic-acid-treated chicken erythrocytes (1/32-1/64), as well as untreated chicken erythrocytes (1/16-1/64). They adhered well to MDBK and FL cells. Haemagglutination by them was not inhibited with D-mannose. In six biovar B strains, the haemagglutination titre was low for chicken erythrocytes and showed no increase for tannic-acid-treated chicken erythrocytes. These strains exhibited a weak ability to adhere to MDBK and FL cells.

The structure of Mn/Sb multilayered films has been investigated by transmission electron microscopy. Plan views of an Sb(300 A)/Mn(40 A)/Sb(100 A) sandwich film reveal the epitaxial growth of a NiAs-type intermetallic compound MnSb formed by the interfacial reaction. The orientational relationships between the MnSb and Sb layers are (00.1)MnSb||(00.1)Sb and 〈110〉MnSb||〈110〉Sb. The cross-sectional images of a [Mn(1 A)/Sb(50 A)]90 superlattice film reveal the periodic and coherent stacking of Sb layers and MnSb ‘monolayers'. MnSb ‘monolayers’ grow pseudo-morphologically between Sb layers. Fine structures of ‘monolayer’ MnSb are somewhat disordered; the layer thickness fluctuates in the range of one monolayer and atom layer steps are observed.

Fe-Mg superlattices are synthesized by UHV deposition and the magnetic properties are studied from Mossbauer spectroscopy, polarized neutron and magnetization measurements. An Fe monolayer sandwiched in between Mg layers is ferromagnetic and the easy direction is along the film normal.